The present invention relates to a semiconductor device, and, more particularly, to a semiconductor device with a capacitor and a fuse, which can prevent oxidation of the fuse and generation of cracks around the fuse upon blowing of the fuse, and a method for manufacturing the same.
While manufacturing a semiconductor memory such as a dynamic random access memory (DRAM), chips having inoperable memory cells partially formed therein can be made. Such defective memory cells are “replaced” with previously produced redundancy cells (in the chip) via a repairing process so that the chip of the semiconductor memory can operate normally without being affected by the inoperable memory cells, thereby improving a yield of the chip.
During the repairing process, a program is carried out within inner circuits to select the defective memory cells and change addresses of the defective memory cells to addresses of the redundancy cells. Therefore, in practical use, a line of the redundancy cells is selected to substitute a line of the defective cell in response to an input of an address signal corresponding to the line of the defective memory cells. One approach for such a program is a blowing method by which the defective line is burnt cut by a laser beam. Here, the line cut by the laser beam is referred to as a “fuse,” and a cut portion and a region surrounding the cut portion are referred to as a “fuse box.”
Currently, the fuse is formed of a metallic material rather than a polysilicon material to increase an integration degree and speed of the semiconductor memory. Corresponding to this, the fuse is formed along with a capacitor by forming the fuse with metal for a capacitor plate electrode having a metal-insulator-metal (MIM) structure, thereby simplifying a semiconductor manufacturing process.
Meanwhile, in the case where the fuse is formed to comprise the metal layer for the plate electrode deposited on a dielectric layer of the capacitor, if a metal layer for the plate electrode has properties vulnerable to oxidation, defects can occur when blowing the fuses.
FIGS. 1A and 1B show defects generated when blowing the fuse of the semiconductor device which comprises a capacitor and the fuse.
Referring to FIG. 1A, when blowing a fuse 30 of a fuse box as indicated by reference numeral 32, a metal layer of the blown fuse is exposed to atmosphere, causing volatile components contained in the metal layer to be out-gassed to the atmosphere. Accordingly, oxygen (O2) can be further easily infiltrated into a site where the volatile components are out-gassed, causing oxidation of the metal layer. The oxidation of the metal layer constituting the fuse 30 can generate various defects on an interlayer dielectric, causing a problem such as a fuse blowing.
As shown in FIG. 1B, when the metal layer constituting the fuse 30 is oxidized because of infiltration of oxygen (O2), a crack 34 is created in the interlayer dielectric due to oxidation, and propagates to an adjacent fuse which was not involved in the blowing operation, thereby causing defective fuses upon a high acceleration stress test (HAST) process.